Power supply having low quiescent consumption

ABSTRACT

Electronic circuitry and methods are provided. Electrical energy is coupled to a transformer by way of line filter of a power supply. A clipper circuit limits the alternating-current voltage applied to the primary side. A voltage tripler receives output from the secondary side of the transformer and a resulting voltage is coupled to a voltage regulator. At least one regulated direct-current voltage is output to a load and is maintained while a current pulse is applied to a predetermined device. The electronic circuitry conforms to pending power conservation requirements for computers and other equipment.

BACKGROUND

Numerous desktop computers and other devices are designed to assume alow power-consumption or “deep standby” mode during non-use or otheridle periods. Applicable laws and regulations in this area are becomingmore stringent as the need to conserve resources is recognized asessential to a sustainable global community. However, many existingpower supplies and other circuit designs cannot conform to present orpending power conservation directives. The present teachings address theforegoing concerns.

BRIEF DESCRIPTION OF THE DRAWINGS

The present embodiments will now be described, by way of example, withreference to the accompanying drawings, in which:

FIG. 1 depicts a schematic diagram of electronic circuitry according toone embodiment;

FIG. 2 depicts a block diagram of a computer system according to oneembodiment;

FIG. 3 is a flow diagram depicting a method according to one embodiment.

DETAILED DESCRIPTION Introduction

Means and methods for conserving electrical energy within a computer orother load are provided by the present teachings. Electrical energy iscoupled to a transformer by way of line filter of a power supply. Aclipper circuit limits the alternating-current voltage applied to theprimary side of the transformer. A voltage tripler receives output fromthe secondary side of the transformer and a resulting unregulatedvoltage is coupled to a voltage regulator. At least one regulated directcurrent voltage is output to a load and is maintained while a currentpulse is applied to a predetermined device. Electronic circuitry of thepresent teachings conforms to pending power conservation requirementsfor computers and other equipment.

In one embodiment, an electronic circuit includes a pair of diodesconfigured to define a voltage clipper. The electronic circuit alsoincludes a transformer having a primary side and a secondary side, theprimary side electrically connected across the voltage clipper. Theelectronic circuit also includes a voltage tripler electrically coupledto the secondary side of the transformer and configured to output anunregulated voltage. The electronic circuit further includes a voltageregulator electrically coupled to the voltage tripler and configured tooutput one or more regulated direct-current voltages.

In another embodiment, a method includes clipping an alternating-currentvoltage applied to a primary side of a transformer using a voltageclipper. The method also includes tripling a voltage output from asecondary side of the transformer using a voltage tripler. The methodadditionally includes electrically coupling an output from the voltagetripler to a voltage regulator using a diode. The method furtherincludes outputting at least one regulated direct-current voltage fromthe voltage regulator to a load.

First Illustrative Embodiment

Reference is now directed to FIG. 1, which depicts a schematic diagramof electronic circuitry 100. The circuitry 100 is illustrative andnon-limiting with respect to the present teachings. Thus, other circuitscan be configured and/or operated in accordance with the presentteachings.

The circuitry 100 includes a pair of power input nodes 102 and 104 thatreceive alternating-current (AC) electricity from an external sourcesuch as a power distribution utility. For non-limiting example, apotential of two-hundred thirty volts root-mean-square (RMS) at fiftyHertz frequency is provided between nodes 102 and 104 from a utilitysource. Electricity having other voltage or frequency specifications canalso be used.

The circuitry 100 also includes a capacitor 106, an inductor 108 and acapacitor 110 that are configured to define a pi-type line filter 112 ofa power supply. The line filter 112 is of known design and operation toone having ordinary skill in the electrical arts. The line filter 112 iscoupled to receive electrical energy from the input nodes 102 and 104,and is defined by an output node 114. The output node 114 can beconnected to other portions (not shown) of the power supply such aspower-factor correction circuitry, etc. Circuitry according to thepresent teachings is described hereinafter.

The circuitry 100 also includes a diode 116 and a diode 118 that areelectrically coupled in parallel, complimentary polarity orientation soas to define a bipolar (or bidirectional) voltage clipper (or limiter)120. Each of the diodes 116 and 118 is defined by a silicon diode havinga typical forward voltage of zero-point-six volts. Other suitable diodesor voltage clipper configurations can also be used. The voltage clipper120 is electrically connected to node 104, and is electrically coupledto node 114 by way of the capacitor 110. The voltage clipper 120 is alsoelectrically coupled to opposite ends of the inductor 108 by way ofrespective resistors 122 and 124.

The circuitry 100 also includes a transformer 126 having a primary side(inductor) 128 and a secondary side (inductor) 130. The transformer 126is connected across the voltage clipper 120 such that, during normaloperation, alternating-current potential applied to the primary side 128is limited to about plus-and-minus zero-point-six volts (i.e.,zero-point-six volts absolute value). In one embodiment, the transformer126 is defined by a primary side 128 direct-current resistance of aboutten Ohms, a primary side 128 inductance of about sixty-eightmilliHenrys, a turns ratio of eight, and a secondary side 130 inductanceof about four-point-three-five Henrys. Thus, in one embodiment, thetransformer 126 is selected such that an alternating-current input tothe primary side 128 of zero-point-six volts peak results in an outputfrom the secondary side 130 of about four-point-eight volts peak underno-load conditions.

The circuitry 100 also includes a capacitor 132 that couples one end ofthe secondary side 130 of the transformer 126 to a node 134 (labeled“A”), while that same end of the secondary side 130 is also coupled to anode 136 (labeled “B”). The opposite end of the secondary side 130 isconnected to a node 138 (labeled “C”).

The circuitry 100 further includes three respective Schottky diodes 140,142 and 144, and four respective capacitors 146, 148, 150 and 152. TheSchottky diodes 140-144, and the capacitors 132 and 146-152, areconfigured to define a voltage tripler 154. The voltage tripler 154receives electrical output from the transformer 126 and provides anunregulated electrical potential between node 138 and an output node 156that is about three times greater in peak voltage value than thatpresent between nodes 136 and 138.

The circuitry 100 also includes a filter capacitor 158, and a pair ofcapacitors 160 and 162 arranged in series-circuit configuration.Additionally, the circuitry 100 includes three resistors 164, 166 and168 arranged to define a voltage divider. The circuitry 100 includes atransistor 170 and a transistor 172 that are respectively coupled to bebiased by way of the three resistors 164-168 (i.e., the voltagedivider).

The transistor 170 is configured provides a regulated direct-currentoutput voltage of about five volts at a node 174, while the transistor172 is configured to provide a regulated direct-current output voltageof about three-point-three volts at a node 176. The capacitors 158-162,the resistors 164-168 and the transistors 170-172 are collectivelyconfigured to define a voltage regulator 178. The voltage regulator 178receives electrical energy from the voltage tripler 154 by connection tonode 138 and by electrical coupling to node 156 through a Schottky diode180. The Schottky diode 180 provides temporary voltage isolation whenunregulated voltage at node 156 is used to change the state of alatching relay (e.g., latching relay 222 of FIG. 2) and capacitor 158becomes the current source for voltage regulator 178 during this event.It is noted that the transistor 172 is configured to derive theregulated voltage at node 176 from the regulated voltage at node 174.

The respective circuitry 100 components 116-180, inclusive, collectivelydefine a co-auxiliary power supply 182 in accordance with the presentteachings. The co-auxiliary power supply 182 is configured to operatewith less than two-hundred milliWatts of power consumption. Table 1below provides illustrative and non-limiting values for the componentsof the co-auxiliary power supply 182.

TABLE 1 Co-Auxiliary Power Supply 182 Element/Device Value/ModelNotes/Vendor Diode 116 MURS120 ON Semiconductor Diode 118 MURS120 ONSemiconductor Resistor 122 1M Ohms (any) Resistor 124 400k Ohms (any)Transformer 126 ST-3-28 Signal Transformer, Inc. Capacitor 132 22 uF 16V Diode 140 BAT54 Vishay Americas Diode 142 BAT54 Vishay Americas Diode144 BAT54 Vishay Americas Capacitor 146 22 uF 16 V Capacitor 148 22 uF16 V Capacitor 150 22 uF 16 V Capacitor 152 22 uF 16 V Capacitor 158 470uF 16 V Capacitor 160 1 uF 16 V Capacitor 162 1 uF 16 V Resistor 164191k Ohms (any) Resistor 166 47.5k Ohms (any) Resistor 168 110k Ohms(any) Transistor 170 MMBT3904 Fairchild Semiconductor Transistor 172MMBT3904 Fairchild Semiconductor Diode 180 BAT54 Vishay Americas

First Illustrative System

FIG. 2 is a block diagram depicting a computer 200 according to anembodiment of the present teachings. The computer 200 is illustrativeand non-limiting in nature, and is intended to depict one of any numberof possible applications of the present teachings. Thus, other computersand systems can also be defined and used in accordance with the presentteachings.

The computer 200 includes a processor 202, main memory array 204, hostbridge 206 and video driver 208 that are respectively configured andoperative as is known of one having ordinary skill in the computer arts.The computer 200 also includes a firmware hub 210 defined by read-onlymemory (ROM) including program code executable by the processor 202. Thecomputer 200 further includes input/output 212, and a second bridge ICH214. The second bridge ICH 214 bridges a primary expansion bus from thehost bridge 206 to various secondary buses, such as a PCI and a low pincount (LPC) bus.

In accordance with some embodiments, the second bridge ICH 214 comprisesan Input/Output Controller Hub (ICH) manufactured by Intel Corporationof Chandler, Ariz. In the embodiment depicted in FIG. 2, the primaryexpansion bus between the host bridge 206 and the second bridge ICH 214comprises a Hub-link bus, which is a proprietary bus of the IntelCorporation. However, computer system 200 is not limited to a chipsetmanufactured by Intel, and thus other suitable chipsets and thereforeother suitable buses between the bridge devices can be used.

The computer 200 includes a power control circuit 216 that is configuredto coordinate the provision of electrical power to the other variouscircuits and sub-systems of the computer 200 during normal (full-power)operations. The power control circuit 216 is also configured to controlpower conservation within the computer 200 by shutting off electricalpower to various resources of the computer 200 during deep standbyoperation. The power control circuit 216 is also configured to issuesignals as needed in order to transition between deep standby, normal orother operating modes. The power control circuit 216 is coupled to amanually-actuated switch 218 that controls start-up and shut-down of thecomputer 200 in accordance with user input.

The computer 200 also includes a switching power supply 220. The powersupply 220 includes a latching relay 222 that is controlled inaccordance with deep standby and wake-up (i.e., full power) modes ofoperations. The latching relay 222 is configured to enable and disablethe flow of electrical energy within at least a portion of the powersupply 220. The power supply 220 also includes a co-auxiliary powersupply 224 according to the present teachings. In one embodiment, theco-auxiliary power supply 224 is defined and configured as describedabove in regard to the co-auxiliary power supply 182. Other co-auxiliarypower supplies can also be used. The co-auxiliary power supply 224 isconfigured to provide three-point-three volts and five volts ofelectrical energy so as to enable a transition from a deep standby modeto fully-operational mode for the computer 200. The switching powersupply 220 and the co-auxiliary power supply 224 each receive utilityline power through a line filter 232 by way of a pair of input nodes234.

The computer 200 also includes a battery 226 configured to provideelectrical energy as needed in order to transition from a deep standbymode to fully operational (i.e., awake) mode for the computer 200. Thecomputer 200 include a three-volt dual circuit 228 configured to receivedirect-current (DC) electrical potential from each of the co-auxiliarypower supply 224 and the battery 226 by way of a pair of respectiveSchottky steering diodes 230.

It is noted that the Schottky steering diodes 230 results in about azero-point-three volt drop in the respective potentials being providedto the three-volt dual circuit 228. The three-volt dual circuit 228 isalso configured to provide three volts to the power control circuit 216and other resources of the computer 200 as needed to power a Real TimeClock (RTC, not shown) and to enable deep standby and full-power (i.e.,awake) modes of operation. Illustrative normal operation of the computer200 is described hereinafter.

First Illustrative Method

FIG. 3 is a flow diagram depicting a method according to one embodimentof the present teachings. The method of FIG. 3 includes particularoperations and order of execution. However, other methods includingother operations, omitting one or more of the depicted operations,and/or proceeding in other orders of execution can also be usedaccording to the present teachings. Thus, the method of FIG. 3 isillustrative and non-limiting in nature. Reference is also made to FIG.2 in the interest of understanding the method of FIG. 3.

At 300, primary and co-auxiliary power supplies for a computer (or otherload) operate normally. For purposes of non-limiting illustration, it isassumed that a switching power supply 220 and a co-auxiliary powersupply 224 operate contemporaneously, receiving electrical energy from autility line source by way of a pair of input nodes 234.

At 302, a standby mode of operation is initiated. For purposes of theongoing illustration, it is assumed that a computer 200 has been leftidle for some predetermined period of time and is automatically assuminga deep standby condition. Transition to the deep standby mode caninclude any number of required or desired operations, such as recordingthe present operating state to memory 204, cessation of networkcommunications via input/output 212, downloading register contents froma processor 202 to a non-volatile memory, etc.

At 304, the primary power supply is de-energized at the source. Forpurposes of illustration, it is assumed that the latching relay 222 isactuated into a reset (i.e., open switch) condition, thus disconnectingline utility power from at least a portion of the switching power supply220. The switching power supply 220 is now effectively inactivated anddoes not provide any electrical energy to the balance of the computer200.

At 306, the co-auxiliary power supply continues normal operation by wayof the line filter. For purposes of illustration, it is assumed that theco-auxiliary power supply 224 continues to receive electrical energyfrom a utility source by way of the line filter 232. The co-auxiliarypower supply 224 also continues to provide three-point-three volts ofdirect-current potential that is electrically coupled to the three-voltdual circuit 228, and five volts of direct-current potential that iselectrically coupled to the power control circuit 216. In turn, thepower control circuit 216 remains active and prevents electrical powerfrom being provided to select other portions of the computer 200 duringthe deep standby mode.

At 308, a wake-up (i.e., full power) mode of operation is initiated. Forpurposes of the ongoing illustration, it is assumed that the computer200 has received some user input by way of, for non-limiting example,button press. The computer 200 is thus beginning to reinstate a normal,full power operating mode. Other scenarios can also occur.

At 310, the co-auxiliary power supply provides an electrical currentpulse to a latching relay. For purposes of illustration, theco-auxiliary power supply 224 provides an unregulated electrical pulseto the latching relay 222, enabling the latching relay 222 to assume aset (i.e., closed switch) condition. The co-auxiliary power supply 224continues to provide three-point-three volts and five voltsdirect-current power in an uninterrupted manner during the provision ofthe electrical pulse.

At 312, the primary power supply is reenergized at the source. Forpurposes of illustration, it is assumed that the set condition of thelatching relay 222 reconnects line utility power within the switchingpower supply 220. The power supply 220 is now returned to a full-poweroperating status.

At 314, the computer resumes normal operations. It is assumed that areturn to normal (i.e., full-power) operations can include any number ofrequired or desired operations such as, for non-limiting illustration,retrieving the most recent operating state from memory 204,reestablishment of network communications via input/output 212,uploading register contents from a non-volatile memory into theprocessor 202, etc.

The foregoing method is illustrative of any number of methodscontemplated by the present teachings. In general, and withoutlimitation, primary and co-auxiliary power supplies operatecontemporaneously within a computer or other load device. At some pointin time, a deep standby mode of operation is manually or automaticallyinitiated. The primary power supply is disconnected from a source ofline power by way of latching relay and the primary power supply iseffectively de-energized. Other operations and steps in preparation forassuming the standby mode can also be performed as needed. Theco-auxiliary power supply continues normal operation despite thede-energized state of the primary power supply.

At some later point in time, a wake-up (i.e., full power) mode ofoperation is manually or automatically initiated. The co-auxiliary powersupply provides electrical energy as needed in order to perform orinitiate the wake-up sequence, including provision of a pulse of energyin order to set the latching relay within the primary power supply. Theprimary power supply then assumes a full-power operating mode, and thecomputer or other load is returned to normal operating status.

In general, the foregoing description is intended to be illustrative andnot restrictive. Many embodiments and applications other than theexamples provided would be apparent to those of skill in the art uponreading the above description. The scope of the invention should bedetermined, not with reference to the above description, but shouldinstead be determined with reference to the appended claims, along withthe full scope of equivalents to which such claims are entitled. It isanticipated and intended that future developments will occur in the artsdiscussed herein, and that the disclosed systems and methods will beincorporated into such future embodiments. In sum, it should beunderstood that the invention is capable of modification and variationand is limited only by the following claims.

1. An electronic circuit, comprising: a pair of diodes configured todefine a voltage clipper; a transformer having a primary side and asecondary side, the primary side electrically connected across thevoltage clipper: a voltage tripler electrically coupled to the secondaryside of the transformer and configured to output an unregulated voltage;and a voltage regulator electrically coupled to the voltage tripler andconfigured to output one or more regulated direct-current voltages. 2.The electronic circuit according to claim 1 further configured to beelectrically coupled to a line filter of a power supply.
 3. Theelectronic circuit according to claim 2, the line filter defined by api-type line filter of a power supply.
 4. The electronic circuitaccording to claim 1, the voltage clipper configured to limit analternating-current voltage applied across the primary side of thetransformer to not greater than about seven-tenths of a volt absolutevalue.
 5. The electronic circuit according to claim 1, the voltagetripler including a plurality of Schottky diodes and a plurality ofcapacitors.
 6. The electronic circuit according to claim 1, the voltageregulator comprising: a plurality of resistors configured to define avoltage divider; a first transistor biased by way of the voltage dividerand configured to output a first regulated direct-current voltage; and asecond transistor biased by way of the voltage divider and configured tooutput a second regulated direct-current voltage less than the firstregulated direct-current voltage.
 7. The electronic circuit according toclaim 6, the second transistor configured to derive the second regulateddirect-current voltage from the first regulated direct-current voltage.8. The electronic circuit according to claim 1 further comprising adiode configured to electrically couple the voltage tripler to thevoltage regulator.
 9. The electronic circuit according to claim 1, thevoltage regulator configured such that the one or more regulateddirect-current voltages are continuously provided while the voltagetripler provides an electrical current pulse to a predetermined load.10. The electronic circuit according to claim 9, the predetermined loadbeing defined by a latching relay.
 11. The electronic circuit accordingto claim 1, the electronic circuit defined by a power dissipation ofless than two hundred milliwatts.
 12. The electronic circuit accordingto claim 1, the transformer defined by a primary side direct-currentresistance of less than about ten Ohms.
 13. A method, comprising:clipping an alternating-current voltage applied to a primary side of atransformer using a voltage clipper; tripling a voltage output from asecondary side of the transformer using a voltage tripler; electricallycoupling an output from the voltage tripler to a voltage regulator usinga diode; and outputting at least one regulated direct-current voltagefrom the voltage regulator to a load.
 14. The method according to claim13 further comprising electrically coupling the primary side of thetransformer to a source of alternating-current electricity using a linefilter of a power supply.
 15. The method according to claim 13 furthercomprising providing an electrical pulse from the voltage tripler to apredetermined entity while maintaining the at least one regulateddirect-current voltage output from the voltage regulator to the load.